sterilization and disinfection in dentistry

1. STERILISATION AND
DISINFECTION IN
DENTISTRY

2. CONTENTS
 INTRODUCTION
 TERMINOLOGIES
 ROUTES OF CONTAMINATION
 OSHA REGULATIONS
 PERSONAL BARRIER PROTECTION IN THE DENTAL
OFFICE
 OPERATORY ASEPSIS
 PROCEDURES BEFORE STERILISATION
 STERILISATION
 MONITORING STERLIZATION
 DISINFECTION
 NEWER METHODS OF STERLIZATION

3.  HAND-PIECE STERLIZATION
 CONTROL INFECTION FROM AEROSOL
 DENTAL CONTROL WATER UNIT SYSTEMS & HAND-PIECE
ASEPSIS
 INFECTION CONTROL FOR IMPRESSIONS
 INFECTION CONTROL FOR EXTRACTED TEETH USED FOR
RESEARCH AS PER OSHA & CDC
 NEEDLE STICK INJURY
 FUTURE CONSIDERATIONS
 DISPOSAL OF WASTE
 CONCLUSION

4. INTRODUCTION
• Infection control has become an integral part of dental
practice.
• Presently there are clearly defined techniques and protocols
for sterilization of various materials and instruments used for
restorative treatment.
• Main concern is for upper respiratory tract infections, herpes
simplex, TB, Hepatitis B, AIDS etc.
• Hence it is essential for dental team to have a clear
understanding of infection transmission & various methods to
control them.

5. • All infected patients cannot be identified by medical
history, physical examination or laboratory tests, Centers
for Disease Control & Prevention (CDC) recommends
that blood and body fluid precautions be used consistently
for all patients.
• These precautions, referred to as “ universal precautions ”
must be observed routinely of all dental patients.

6. TERMINOLOGIES
• CLEANING:
Process which removes visible contamination, but does not
necessarily destroy microorganisms.
• ASEPSIS:
Prevention of contact with pathogens.[barrier protection, sterilization,
disinfection]
• ANTISEPSIS
Procedure or application of an antiseptic which inhibits the growth of
microorganisms, while remaining in contact with them, but not
necessarily imply sterility.

7. • STERLIZATION:
Process by which an article, surface or medium is freed of all
living microorganisms either in the vegetative or spore state.
• DISINFECTION:
Destruction or removal of all pathogenic organisms, or
organisms capable of giving rise to infection.
• DISINFECTANT:
Chemical substance, which causes disinfection. It is used for
non-vital objects to kill vegetative pathogenic organisms, but
not necessarily spore forms or viruses.

8. ROUTES OF CONTAMINATION
• DIRECT TRANSMISSION:
Occurs by direct contact with body fluids through a
previously damaged skin/mucous membrane with a lesion,
organisms/debris while performing intra-oral procedures.

9. • INDIRECT CONTAMINATION:
The invisible trail of saliva left on contaminated surfaces
like handles, operatory units etc are potential sources of
contamination to personnel & patients
Cross-contamination of patients by such sources
have been documented.

10. • AIR BORN CONTAMINATION:
• High-speed hand piece capable of creating air-borne contamination…
• Aerosols consists of invisible particles ranging from
50mm to approx 5mm that remain suspended in the air & breathed for
hours…
• Mists become visible in a beam of light consists of droplets estimated to
approach or exceed 50mm.
Heavy mists tend to settle gradually from air after 5 to 15 mm…

11. • Spatter consists of particles larger than 50mm and are
even visible splashes.
Has distinct trajectory, usually falling within 3ft of
the patients mouth, having potential for coating the face
and outer garments of the attending personnel.

13. OSHA REGULATIONS FOR
EMPLOYERS
• Must provide HBV immunization to employees within 10days of
employment.
• Must implement engineering control to reduce production of spatter,
mists, aerosols… rubber dam, high volume suction, etc.,
• Practice control precautions-telephone, handles, not be touched with
soiled gloves.
• Employers must require that standard precautions be observed to
prevent contact with blood and other potentially infectious materials.

14. • Must provide instructions to wash hands after removing gloves &
flush eye/mucosa of any contact with blood/saliva.
• Prescribe safe handling of needles. They should not be bend/cut.
• Prescribe disposal of single-use needles, wires, carpules, sharps in
red/biohazard labeled bags.
• Teeth must not be discarded into trash, but can be given to the
patient or discarded in sharps container

15. • Basket/cassette/puncture resistant bags used for reusable
sharp instruments.
• Prohibit eating, drinking, handling contact lenses,
application of cosmetics , use of mobiles in contaminated
areas.
• Blood/contaminated specimens stored in leak-proof
containers.
• Provide necessary PPE ( Personal Protective Equipment)
such as gloves, gowns, or masks.
• Ensure proper use & discard of PPE or prepare it properly
for reuse.

16. • Attend regularly to housekeeping requirements &
prescribe written schedules for cleaning/decontaminating
work surfaces/floors.
• Contaminated sharps are regulated waste & should be
discarded in hard-walled containers.
• Reusable sharps placed in basket in hard-walled
containers to be transported to clean up areas.
• Laundering of protective garments/soiled linens.

18. PERSONAL BARRIER TECHNIQUE
1) Hand washing:
 Hand cleansers such as 3% p-chlorometaxylenol or 4%
chlorhexidine gluconate can be used.
2) Gloves:
 Fresh gloves must be worn for every patient.
 Avoids contamination by occult blood and help to prevent painful
& transmissible herpetic infections to fingers (whitlow) & hands.
 Gloves should not be washed with hand soaps [ reduces gloves
integrity, leaving personal more vulnerable].
 Types- latex gloves, polyethylene gloves.
 They come in 4 mil & 8 mil thickness.

19. 3) Protective Eyewear, Masks & Hair protection:
 Consists of goggles or glasses with solid side shields.
 Protect against aerosols.
 Mask should be changed between every patient or whenever it becomes
moist or visibly soiled.
 Changing time – 20min in aerosol environment and 60 min on non-aerosol
environment.
 Masks should have atleast 95% filtration efficiency for particles 3 to 5 µm
diameter.
4) Overgloves:
 Made of lightweight, inexpensive, clear plastic.

20. 5) Protective overgarments:
 Made of cotton or synthetic fiber similar to an isolation garment
material protect the skin.
 Overgarment should be changed whenever becomes moist or
visibly soiled.
 Wearing contaminated garments to home or out the clinic area
should not occur.
 Laundered on daily basis separately from other garments.
 Hot water (70°C or 158° F) or cool water containing 50-150 ppm
of chlorine provided by liquid bleach would provide more
antimicrobial action.

21. Standard rub-in technique for hygienic hand
disinfection
• For hygienic hand disinfection, apply the hand disinfectant onto
dry palms and rub in up to the wrists for 30 seconds according to
the steps listed below.
• Perform the movements of each step five times.
• After completion of the 6th step, the individual steps are to be
repeated until the rubbing time indicated has been attained.
• Important: Make sure that the hands remain moist during the
entire rubbing time. If necessary, use more hand disinfectant.

22. Rub palm to palm.
In addition the
wrists, if required
1 2
Right palm over
the back of the
left
hand – and vice
versa
3
Rub palm to palm
with interlaced
spread fingers
Rub the backs of the
interlocked fi ngers
on the opposing
palms
4
Rub the right thumb in the
closed palm
of the left hand using a
circular motion
– and vice versa
Rub the closed fi
ngertips of the right
hand on the left
palm using a circular
motion – and vice
versa

23. HAND CARE PROTOCOL
REMOVE JEWELLERY
HAND WASH USING RECOMMENDED TECHNIQUE
RINSE HAND THOROUGHLY
DRY HANDS WITH DISPOSABLE TOWEL
DISINFECT WITH ALCOHOL HAND RUB
INVASIVE PROCEDURE NON-INVASIVE PROCEDURE
AT LEAST 2-5 ml ALCOHOL 3min EXAMINATION GLOVES
TREATMENT PATIENT
HAND NOT VISIBLY
CONTAMINATED REMOVE & DISCARD GLOVES
HAND VISIBLY NEXT PATIENT CLEAN & DISINFECT – ALCOHOL 30
CONTANMINATED sec

24. OPERATIVE ASEPSIS
• CRITICAL ITEMS:
 Surgical and other instruments that cut or penetrate soft
tissues or bone are classified as critical & should be
sterlized after each use.
Includes- needles, scalpels, endodontic instruments, burs
& scalers.

25. • SEMI-CRITICAL ITEMS:
 Instruments that contact oral tissues like air-water syringe
tip, suction tips, prophy angle and hand-pieces.
 Other instruments are handled during treatment like lamp
handle, switches, chair control buttons etc.
 Must be removed for cleaning & sterilization, unless they are
disposable plastic covers( applies especially to air-water
syringe).
They should not be disinfected only.
 They should be covered, cleaned, and sterilized or discarded.

27. • NON-CRITICAL ITEMS :
 These are the environmental surfaces, such as chairs,
floors, walls and supporting equipments not touched
ordinarily during treatment.
 Contaminated non-critical items require cleaning and
disinfection.
• Ex: pulp oximeter, stethoscope, light switches,
dental chair

28. • CDC recommends:
1. Critical and semicritical inst --- heat sterlized
2. Semicritical sensitive to heat --- high level disinfection after
cleaning
3. Non critical inst --- intermediate to low level disinfection
after cleaning

29. PROCEDURES BEFORE STERILISATION
• Pre-soaking of instruments:
1) Soaked in chemical disinfectant like gluteraldehyde or synthetic
phenol for 30min.
2) Pre-soaking the contaminated instruments keeps them wet until a
thorough cleaning can occur. This prevents the blood or saliva from
drying on instrument facilitating cleaning.
• Pre-sterilization cleaning of instruments:
1) Manual method-
Hard brush with stiff bristles and detergent soln.
2) Ultrasonic method-
Ultrasonic cleanser operating at 40 degree Celsius & 35 KHz for
2-20 min.

30. • After removal of debris, instruments which are likely to rust should
be dipped in rust inhibiter ( 2% sodium nitrate).
• The clinician should drain and dry the instruments in cassettes or
carefully spill the basket of instruments onto an absorbent towel on a
tray.
• The towels are considered as contaminated items.
• Still wearing protective gloves , the clinician properly packages the
inst. together with internal or external sterlization indicators suited to
sterlization process used.

33. STERILIZATION
SUNLIGHT:
• Possesses appreciable bactericidal activity.
• Spontaneous sterilization occurs under natural light if kept in
sunlight for 12 hrs.
• Action is primarily due to ultraviolet rays.
DRYING:
• Moisture is essential for growth of bacteria.
• Four-fifth of the weight of the bacterial cell is due to water. Drying
in air therefore has deleterious effect on many bacteria.

34. HEAT:
• Most reliable method of sterilization and should be the
method of choice unless contraindicated.
Mode of action:
• Dry heat protein denaturation, oxidative damage & toxic
effect of elevated levels of electrolytes.
• Moist heat denaturation & coagulation of protein.
Thermal death time: It is the minimum time required to kill a
suspension of organisms at a predetermined temperature in a
specified environment.

35. • DRY HEAT:
I) INCINERATION:
• Excellent method for destroying materials such as
contaminated cloth, animal carcasses & pathological
materials.
II) HOT AIR OVEN:
• Widely used method.
• Glassware, forceps, scissors, scalpel, all-glass syringes,
swabs, some pharmaceutical products such as liquid
paraffin, dusting powder, fats & grease can be sterilized.

36. Recommended temperature & duration:
TEMPERATURE(°)
160
170
180
190
HOLDING TIME(min)
45
18
7.5
1.5

37.  Precautions:
 Should not be overloaded.
 Must be fitted with fans for distribution of hot air.
 Allowed to cool for 2hrs.
 Advantages:
 No corrosion .
 Cost effective.
 Items are dry after cycle.
 Disadvantages:
 Longer sterlization time.
 Cannot sterlize liquids.
 May damage plastic & rubber items.
 Not suited for heat sensitive inst like NiTi whose property changes
by increase in temperature.

38. HOT AIR OVEN

39. RAPID HEAT STERLIZATION (forced air type)
• Uses internal air flow system at 374°F for 6min for unwrapped
instruments &12min for wrapped instruments.
• Advantages:
1] No corrosion.
2] Short cycle.
3] Items are dry after cycle.
4] maintains the sharpness of the instruments
• Disadvantages:
1] cannot sterilize liquids.
2] May damage plastic and rubber items.

41. Glass Bead Sterilizer
• Used for small instruments like burs, endodontic instruments, absorbent
points , etc.
• Temperature range – 450°F(218°C) & 475°F(246°C) for 5-15 sec.
• Root canal inst.- 5 sec, absorbent points & cotton pellets- 10 sec.
• Usually uses table salt which consists app 1% of sodium silico-aluminate,
sodium carbonate or magnesium carbonate.
• It can be poured immediately & does not fuse under heat. Salt can be
replaced by glass beads of diameter smaller than 1mm.(larger beads are not
efficient in transferring heat due to large air spaces.)
• These sterlizers are used to consists of either hot salt or glass beads as a
medium for dry sterlization.
• Hottest part is along the outer rim.

42. • DISADVANTAGE:
Handle portion is not sterilized & therefore these articles
are not entirely “ sterile”.

43. MOIST HEAT
• Temperature below 100°C:
• PASTURIZATION OF MILK:
Milk is heated at either 63°C for 30 min (holder method)
or 72°C for 15-20 min (flash method) followed by cooling
quickly to 13°C or lower.
Non-sporing pathogens are destroyed.
Vaccines of non-sporing bacteria are best inactivated in
special vaccine baths at 60°C for an hour.

44. • Temperature at 100°C:
• BOILING:
• Vegetative forms of bacteria are killed almost
immediately at 90-100°C.
• Time required is 10-30min.
• Not suitable for sterilizing instruments for surgical
procedures & should be regarded as only as a means of
disinfection.

45. • TYNDALIZATION ( INTERMITTENT
STERLIZATION):
• Used for sterilization of media containing sugars or
gelatin.
• An exposure of 100°C for 20 min on 3 successive days is
used.
• Principle first exposure kills all vegetative bacteria,
and the spores, since they are in a favorable medium, will
germinate and be killed on subsequent occasions.

46. AUTOCLAVE
• Sterilization is due to latent heat of vaporization present in moist
heat.
• When steam condenses on contact with cooler surfaces, it becomes
water and gives latent heat to that surface.
• Moist heat denatures and coagulates proteins of microorganisms.

47. TEMP TIME PRESSURE
UNWRAPPED
INSTRUMENTS
1340C 3 min 30 psi
WRAPPED
INSTRUMENTS
1210C 15 - 20 min 15 psi
Advantages:
1] Good penetration
2] Time efficient
3] Sterilize water based liquids
Disadvantages:
1] May damage plastic or rubber items.
2] Rust carbon steel instruments & burs.

48. CHEMICAL VAPOUR PRESSURE
STERILIZATION
• Uses a solution of 72% ethanol & 0.23% formaldehyde in
place of water in its autoclave.
• Cycle – 132° C (270°F), 20lbs, 20min.
• ADVANTAGES-
-No corrosion of metals.
-Rapid & efficient cycle time.
-Load comes out dry.

49. • DISADVANTAGES:
-High cost.
-Ventilation or filtration is required to handle
formaldehyde fumes.
-Solution supplied by manufacturer has to be used.
-Hand-pieces cannot be sterilized.

50. ETHYLENE OXIDE STERILIZATION
• Uses automatic devices filled with ethylene oxide gas at temp
below 100° C.
• Colorless liquid with a boiling point of 10.7°C.
• Its highly inflammable & in the concentrations in air greater
than 3%, highly explosive.
• Action is due to its alkylating the amino, carboxyl, hydroxyl
& sulphahydral groups in protein molecules. Also reacts with
DNA & RNA.

51. • ADVANTAGES :-
 Best method to sterilize complex instruments & delicate
materials.
 Operates effectively at low temperatures.
• DISADVANTAGES :-
 High cost.
 prolonged time.
 not practical for dental clinics.
 ethylene oxide gas is potentially mutagenic & carcinogenic.

53. MONITERING STERILIZATION
• Mechanical monitoring:
• Each load must be monitored to document
time/temp/pressure.
• Sterilization indicators are marked with heat-sensitive
dyes to differentiate the packs that have been in the
sterilizer from those that have not.

54. • Chemical indicator strips:
• This provides an inexpensive, qualitative monitor sterilizer
function, operation & heat penetration into packs.
• Chemicals on strip change color & breakdowns/gross
overloading can be identified.
• Biologic monitoring strips:
• Is the accepted weekly monitor of adequate time/temp
exposure.
• Pre-dried spores on absorbent paper are calibrated to be killed
when sterilization conditions are reached & maintained to kill
pathogenic organisms.

55. • Documentation notebook:
• One fixes a single, dated, initialed indicator strip to a
sheet/calendar for each work day followed by weekly
spore report.
• Dated sterilized inst packs, bags, trays provide final
evidence of the sterilization program.

56. DISINFECTION
• Ideal requirements of disinfectants:
1.Broad spectrum
2.Fast acting
3.Not affected by physical factors
4.Non toxic
5.Surface compatibility
6.Residual effect on treated surfaces
7.Easy to use
8.Odorless
9.Economical

57. • ALCOHOLS:
• Ethyl alcohol & isopropyl alcohol are frequently used as surface
disinfectant.
• Effective in concentration of 60-90% in water.
• Act by denaturing bacterial proteins.
• Mainly used as skin disinfectants.
• Isopropyl alcohol is preferred as it is better fat solvent, more
bactericidal & less volatile.
• Disadvantages:
• No action on spores.
• Protein slows action( but 1% mineral acid
or alkali enhances the action)

58. • FORMALDEHYDE:
• Formaldehyde is active against amino group in the protein
molecule.
• It is bactericidal & sporicidal & also has lethal effect on
viruses.
• USES:
• Used to preserve anatomical specimens.
• For destroying anthrax spores in hair & wool.
• 10% formalin containing 0.5% sodium tetraborate is used to
sterilize clean metal instruments.
• Formaldehyde gas is used for sterilizing instruments & heat-
sensitive catheters & for fumigating wards, sick rooms.

59. • Disadvantages:
• Gas is irritant & toxic when inhaled.
• Surfaces which have been disinfected by this agent may
give off irritant vapour for some time after disinfection.

60. GLUTERALDEHYDE
• Action similar to formaldehyde i.e., bactericidal, sporicidal & lethal to
viruses.
• Specially effective against the tubercle bacilli, fungi & viruses.
• 2% gluteraldehyde – cidex requires 20 min immersion time for disinfection
& 6-10 hrs for sterlization.
• Less toxic & irritant to the eyes & skin than formaldehyde.
• No deleterious effects on the cements or the lenses of instruments such as
cytoscopes & bronchoscopes.
• Can be safely used to treat corrugated rubber anesthetic tubes & face
masks , plastic endotracheal tubes, metal instruments & polythene tubing.

61. HALOGENS
• IODINE:
• It is an aqueous & alcoholic solution has been used as a skin
disinfectant.
• Actively bactericidal, with moderate action against spores.
• Compounds of iodine with nonionic wetting or surface-active
agents known as iodophores are claimed to be more active
than the aqueous or alcoholic solutions of iodine.
• 2% iodine in 4% potassium iodide has been used as
endodontic disinfectant.

62. • CHLORINE COMPOUNDS:
• A potent germicide acts by oxidation of bacterial proteins.
• Commonly used as hypochlorites.
• Organic chloramines are used as antiseptics for dressing
wounds.
• CDC recommended 0.05% to 0.5% NaoCl application 3
min for disinfection & 6 hours for sterilization
• NaOCl ( 0.5-5.25 %) is used as an endodontic disinfectant.

63. CHLORINE COMPOUNDS
• Advantages:
– Broad spectram
– Economical
– fast acting
– effective in dilution
• Disadvantages:
– Unstable
– Less active in the presence of organic debris
– Corrodes metal
– Degrades plastics and rubber
– Irritant to skin and mucosa

64. PHENOLS
• Obtained by distillation of coal tar between temperatures
of 170 & 270°C.
• Lister , the father of antiseptic surgery, first introduced
them in surgery (1865).
• Lethal effect is due to their capacity to cause cell
membrane damage, releasing cell contents & causing lysis
eg., carbolic acid.
• Synthetic derivatives like lysols and cresols are active
against wide range of organisms.

65. • Advantages :
– Economical
– Less toxic
– Good surface cleaner
• Disadvantages :
– Not sporicidal
– Irritant to eyes
– Epithelial toxicity

66. CHLORHEXIDINE ( HIBITANE )
• Chlorhexidine (hibitane) is a bisguanide.
• It is relatively non-toxic skin antiseptic against gram +ve & gram-ve
organisms and the aqueous solutions are used for treatment of skin
wounds.
• Gets inactivated in the presence of soaps, pus, plastics,etc.,
• Mainly used for cleaning skin & mucous membrane.
• A 0.2% aqueous solution or 1% gel used for suppression of plaque &
postoperative infection.

67. FORMALDEHYDE GAS:
• Widely employed for fumigation of operation theaters & other rooms.
• After sealing the windows & other outlets, formaldehyde gas is
generated by adding 150g of KMnO4 to 280ml of formalin for every
1000cu.ft (28.3cu.m) of room volume.
• When formaldehyde vapour is generated, the doors should be sealed &
left unopened for 48hrs.

68. BETAPROPIOLACTONE(BPL)
• This is a condensation product of ketone & formaldehyde
with a boiling point of 163°C.
• Has rapid biocidal action but unfortunately has
carcinogenic activity.
• 0.2% BPL is used for sterilization of biological products.

69. SURFACE ACTIVE AGENTS
• Substances that alter the energy relationship at interfaces, producing
a reduction of surface or interfacial tension, are referred to as surface-
active agents.
• Used as wetting agents, detergents & emulsifiers.
• Act on phosphate groups of cell membrane & also enter the cell.
• Active against gram+ve & gram-ve organisms.
• Types:
– Cationic – Ex: Quarternary ammonium compounds
– Anionic – Ex: Soaps

70. NEWER METHODS OF
STERILIZATION
Irradiation :
• Gamma rays, ultraviolet light are used.
• UV radiation may be useful for sanitization of room air to
help control tuberculosis.
• Limitations :
 Poor penetration of oil & incomplete exposure of all
surfaces.
UV light is not highly effective against RNA viruses such
as HIV & is not effective against bacterial spores.

71. Peroxide vapour sterilization:
still under investigations.
Microwave oven:
limited in its effectiveness for metal inst.

72. HAND-PIECE STERILIZATION
-Steam sterilization
-For hand-pieces with metal bearing turbines
-For hand-pieces with lubrication-free ceramic bearing turbine
-Other methods
Steam sterilization:
• Most rapid methods.
• Good utility is obtained if proper cleaning/lubricating done.
For hand-pieces with metal bearing turbines:
 Scrub the metal bearings of hand-pieces at sink with water &
detergent.
 Should be bagged/sheathed/autoclaved

73. For hand-pieces with lubrication- free, ceramic bearing
turbine:
• Do not use chemicals that would damage internal parts
• Consult manufacturer for directions on cleaning fibro-
optics.
• Should be bagged & autoclaved.
• Others: ETOX/Chemical vapour sterilization

74. CONTROL OF INFECTION FROM AEROSOL
• Contamination from spatter & aerosol is created by rotary
instruments.
• Aerosoization of mycobacterium tuberculosis that cause
pulmonary tuberculosis is of great concern.
• Annual tuberculin testing of personal is standard
recommendation in dentistry.
• Rubber dam & high volume evacuators are helpful methods.
• High volume evacuators are 80% effective in reducing aerosol
contamination.
• Universal use of personal barriers, drapes, effective clean up
procedures are must.

75. DENTAL CONTROL UNIT WATER SYSTEMS AND
HAND-PIECE ASEPSIS
• Oral fluid contamination problems of rotary equipment, especially
high speed, involve-
1. Contamination of hand-piece external surfaces & crevices,
2. Turbine chamber contamination that enters the mouth,
3. Water spray retraction& aspiration of oral fluids into the water lines
of older dental units.
4. Growth of environmental aquatic bacteria in water line,
5. Exposure of personnel to spatter & aerosol generated by intra oral
use rotary equipments.

76.  Hand-piece surface contamination control:
Blood and saliva contaminate the surfaces of hand-piece during
various dental procedures.
 Scrubbing with disinfectants- reduces no. of bacteria
 Sterilization.
 Turbine contamination control:
 Contaminated oral fluids may be drawn back into the turbine
chamber by negative pressure created by a venturi effect during
operation or when turbine continues to spin whenever the air is
stopped.
 It has been experimentally shown under extreme conditions on a
laboratory bench, but still during clinical treatments its not proved.

77. • Water retraction system correction:
• Place a one-way check valve
• Systems should be monthly checked.
• Since 1988 nearly all manufacturers produce units cut off
water supply without retraction.

78. Inherent water system contamination:
• Microbes exist in dental unit water line as free floating bacteria & as sessile
form known as biofilm.
• Microbes produce a protective polysaccharide matrix that provides
mechanisms for surface attachment & retention to water line.
• CDC has recommended dental water line should contain less than 500
cfu/mL.
• Clean water reservoir systems combined with disinfection/sterilization of
equipment downstream.
• Educating dental personnel & periodically monitoring compliance with
procedures.

80. INFECTION CONTROL FOR IMPRESSIONS &
OTHER PROSTHETIC ITEMS
Precautions in making impressions & bite registrations:
 Barrier protection by using PPE like gloves, masks, over
garments.
• Wipe material containers with disinfectant after use.
• Trays made of non-aqueous rubber impression materials(
use once & discard)

81. • Transporting to remote laboratory:
• Potentially infectious material in leak-proof containers.
• Labeling/color coding when specimens leave the facility.
• Mandatory to disinfect before sending it to laboratory.

82. Handling & transporting silicone/rubber based
impressions/registrations:
• Remove impression/device from mouth & rinse under tap
water 15sec.
• Place it into clear heat-sealable biohazard-labeled bag.
• Remove gloves & close bag & tape prescription.
• Attach a note to disinfect before use & communicate with
lab personnel.

84. Handling & transporting items of aqueous impression
material/assoc registrations:
• Rinse under tap water 15sec.
• Disinfect with hospital based disinfectant by spraying.
• Rinse & pour cast immediately
• Carefully pack & transport.
• Add a note stating the impression/registration is
disinfected.

85. Handling impressions/assoc
registrations for an on-site laboratory:
• Wear clean uniform/jacket/coat/gown.
• masks, protective eyewear, gloves.
• Designated area to receive items
• All items labeled, disinfected with1:10 dilution 0.5% liquid
chlorine bleach for 10min.
• Rinse impressions.
• Personnel receiving them must wear disposable treatment
gloves.

86. Handling impressions/assoc registrations for an on-site
laboratory:
• All incoming items to the dental laboratory must be properly labeled with
gloved hands, disinfect the impressions by submerging (for 10 min) in 1:10
dilution(0.5%) of household bleach.
• With gloved hands, spray articulators and any related equipment.
• With clean hands, thoroughly rinse the impression under tap water
(15 sec) to remove any residual disinfectant.
• All outgoing items must be properly cleaned & placed in leak-proof
bags/containers.
• Countertops/work surfaces properly cleaned/disinfected.

88. Infection control protocol for extracted teeth collected for
educational research purposes as per OSHA& CDC
• 0.5% sodium hypochlorite- initial collection & storage medium.
• Gloves, masks, protective eye wear should be worn.
• Collection jars should be opened & liquids should be poured from the
jars. Then jars be filled with 5% soluton of bleach ( NaOCl) which
occupy 20% volume of jar.
• After standing in the bleach for atleast one & half hour , collection
liquids should be poured in swear.
• Extracted teeth should be placed on thick paper towel on the desktop.
• Collection jars & their lids should be discarded in biohazard waste
receptacles.

89. • Paper towels should be discarded in biohazard waste receptacles.
Gloves should be removed & discarded.
• Desktops should be cleaned with clinical disinfectant using spray.
• As needed teeth should be removed from jars & rinse with tap
water. After soaking in container of tap water for few min, the
teeth should be rinsed again & then handle sefely with gloved
hands.

90. OUCH – NEEDLESTICK INJURY
• Most infectious diseases transmitted by needle pricks are
1. HIV- 0.3% , 2. Hepatitis C- 3%, 3.Hepatitis B- 30%
• IMMEDIATE MEASURES:
 Encourage the wound to bleed freely.
 Wash thoroughly in running water with 70% alcohol/ antiseptic
hand wash.
 Do not scrub the injury .
 Cover the wound with appropriate dressing.

91. ASSESS THE SIGNIFICANCE OF RISK:
i. TYPE OF INJURY:
- penetrating injury ( greater risk)
- splashes on any mucous membrane – eye, oral mucous membrane , etc.,
ii. DEGREE OF CONTAMINATION:
- high risk if needle has penetrated artery/ vein
iii. INFECTIVITY OF THE MATERIAL TRASFERRED
-contaminated with blood or saliva.
iv. ASK THE PATIENT FOR PRESNCE OF ANY DISEASE
- talk to pts physician regarding pts health status in terms of above
disease.
- collect pts blood to screen for infectious disease.

92. • If the patient is HIV positive:
• For maximum effectiveness postexposure prophylaxis is
recommended that is administered within 1 hr.
• It is 70% effective in reducing the risk of trasmission .
• Prophylaxis regimen- zidovudine, lamivudine, & nelfinavir is
given for no. of weeks depending on the drug protocol.
• Side effects of prophylaxis can be debilitating & therefore routine
propphylaxis foe every needle stick injury cannot be advocated.

93. • If the patient is infectious for Hep B:
• Prior vaccination.
• Antibody titre of both patient & dentist should be checked.
• If the patient is infectious for Hep C:
• No active & passive immunization available.
• No past exposure drug regimen appears effective.

94. • How can it be minimized ( needles, burs, broken plstic, hand
instruments,etc.,)
1. Always pass inst. with sharp end pointing away from any person.
2. Remove burs/ultrasonic tips from hand piesesimmediately after use.
3. Pick up inst immediately.
4. Use one hand technique to resheath the needle.
5. Dispose off sharps into a solid container.
6. Use heavy duty gloves when cleaning instruments prior to
autoclaving.
7. Keep working area well organized & uncultured, with sharps in
separate areas.

95. FUTURE CONSIDERATIONS
• A potential threat on the horizon are prions (PREE-onz).
• Prions are glycoproteins found on cell surfaces. Modified
versions of normal prions cause various sloe-moving,
often fatal disease of nervous system.
• Almost impossible to sterilize in a dental office & they
have affinity for stainless steel.
• killed by some chemical treatments, such as sodium
hydroxide.

96. • Following are the methods followed prior to routine sterlization:
Method 1: immerse contaminated instruments in a pan of 1N NaOH &
heat in a gravity displacement autoclave for normal cycle of 121°
for 30min.
Method 2: immerse in either 1N NaOH or full strength bleach ( 20,000
ppm available chlorine) for 1hr; rinse; transfer to dry, open pan;
heat in gravity displacement autoclave at 121°C for 1hr.
Method 3: immerse in either 1N NaOH or full strength bleach for 1hr;
rinse; transfer to dry open pan; autoclave at 121°C in gravity
displacement autoclave or a conventional autoclave at 134°C for 1
hr.

97. Method 4: immerse and boil in 1N NaOH for 10min.
Method 5: immerse in 1N NaOH or full stregth bleach for 1
hr, rinse and subject to routine sterlization.
Method 6: autoclave at 134°C for 18min.

98. DISPOSAL OF WASTE
• Mercury, silver or other heavy metals should not be poured
down drains.
• Needles disposed in leak-proof bags which has OSHA
biohazard label.
• Separate needles, sharps into hard-walled, leak-proof bags out
of soft trash.
• Sharp & curved ends of inst should be turned away from
recipient's hands while passing inst to other individual.
• Needle-sheath holder/safety device should be used to resheath
the needle with only 1 hand.
• Burs should be removed from hand-pieces when
finished/pointed away from hands, body.

99. BIOMEDICAL WASTE MANAGEMENT
COLOUR CODING TYPE OF
CONTAINER
WASTE
PRODUCTS
TREATMENT
OPTIONS
YELLOW PLASTIC
CONTAINER
HUMAN TISSUES, BODY PARTS,BLEEDING
PARTS,INFECTED COTTON & DRESSING,
SOILEDPLASTER,CASTS,LINES,BLEEDIND
ITEMS CONTAMINATED WITH BLOOD
INCINERATION /
BURNING
RED DISINFECTED
CONTAINER/
PLASTIC BAG
AMALGAM, ZINC OXIDE EUGENOLPASTE,
GREEN STICK COMPOUND, TOOTH OR
BONE FRAGMENTS
DISPOSE IN
SECURE LAND
FIELD
BLUE/WHITE
TRANSLUCENT
DISINFECTED
CONTAINER/
PLASTIC BAG
NEEDLESGLASS, SCALPEL, FORCEPS,
BLADES, METAL CROWNS,BRIDGES,
OTHER USED & UNUSED SHARPS
AUTOCLAVING/
MICROWAVING/
CHEMICAL
TREATMENT
BLACK PLASTIC BAG DISPOSABLE ITEMS LIKE :
SYRINGES, BASE PLATE, IMMPRESSION
MATERIALS, BROKEN DENTURES, PLASTIC
BOTTLES & OTHER CONTAMINATED
PLASTIC ITEMS
DISPOSE IN
SECURE LAND
FIELD

100. CONCLUSION
• Adequate asepsis is a highly critical step in treatment.
• Sterilization procedures should be simple, effective, of
short duration.
• Procedures should not cause any appreciable damage to
dental inst & materials